The overall objective of this application is to support the principal investigator's development in a career focused on patient-oriented research. To accomplish this objective, the proposed program has both training and scientific components. The training component will consist of didactic coursework and preparation of a written thesis, culminating in a Master of Science degree in Clinical Investigation. This innovative degree program is offered by the Department of Epidemiology and Preventive Medicine at the University of Maryland. The coursework will provide training in clinical research methods including biostatistics, responsible research conduct, clinical epidemiology, and design and implementation of research studies. The scientific component of the proposal is focused on the primary prevention of sudden cardiac death. Sudden cardiac death remains a common clinical problem in the United States, with over 350,000 deaths annually. Patients with left ventricular systolic dysfunction are at particularly high risk for the ventricular arrhythmias that precipitate sudden cardiac death. The goal of this research is to develop a new method to identify those patients with systolic dysfunction who are most likely to suffer malignant ventricular arrhythmias. If a high-risk subgroup can be identified, these patients are likely to benefit from prophylactic treatment with an implantable cardioverter-defibrillator (ICD). This proposal is focused on the development of two novel risk stratification techniques that independently quantify dynamic changes in ventricular repolarization: T wave variability and T wave alternans. The scientific program will test the following hypotheses: 1) T wave variability and T wave alternans are both predictors of arrhythmic events among patients with ischemic cardiomyopathy. 2) Patients with increased T wave variability derive a greater mortality benefit from prophylactic ICD implantation.